United States Patent Application Publication No. US 2008/0122904 A1 discloses a cartridge that stores ink, and a printer to which the cartridge is attached. The cartridge is provided with electrodes and the printer is provided with contacts. While the cartridge is inserted into and removed from the printer, a block portion of the cartridge contacts a circuit supporting board of the printer, thereby blocking the electrodes from contacting the contacts. When the cartridge has been completely attached to the printer, the block portion is separated from the circuit supporting board, so that the electrodes can contact the contacts. This enables the printer to access, for example, an IC chip provided at the cartridge through the contact between the electrodes and the contacts.